Introduction: The Endovascular Treatment of Stroke Due to Medium-Vessel Occlusion (ESCAPE-MeVO) trial did not show superiority of thrombectomy over medical management for patients with an acute ischemic stroke secondary to a medium-vessel occlusion (MeVO). The majority of patients included in this trial had an occlusion of the M2/M3 segment of the middle cerebral artery (MCA). The two main branches of the MCA differ in their anatomy and diameter: while the anterior M2/M3 branch is typically of smaller caliber and tortuous, the posterior M2/M3 branch is typically of larger caliber and more straight, making endovascular thrombectomy maneuvers easier and safer. We aimed to assess if the type of branch occlusion (anterior versus posterior branch of the MCA) had any effect on the outcomes after thrombectomy, and if there was treatment effect modification of EVT by the location of the MCA branch occlusion. Methods: This was a sub-group analysis of the ESCAPE-MeVO trial: patients harboring an MCA occlusion were classified into two groups: anterior-MCA-MeVO (occlusion of the anterior branch) and posterior-MCA-MeVO (occlusion of the posterior branch). Outcomes a) between thrombectomy patients with anterior vs. posterior MCA occlusions and b) thrombectomy and best medical care arm patients stratified by occlusion location were compared using descriptive statistics and logistic regression with adjustment for key co-variates. Thrombectomy effect modification by occlusion location was assessed with multiplicative interaction terms. Results: A total of 442 patients were therefore included in the study (170 anterior-MCA-MeVOs and 272 posterior-MCA-MeVOs). Baseline characteristics were similar between groups. Outcomes of patients with anterior-MCA-MeVO occlusion and posterior-MCA-MeVO occlusion treated with thrombectomy were similar, both in terms of angiographic outcomes and clinical outcomes at 3 months follow-up ( Figure 1 ). Finally, there was no significant difference between thrombectomy and standard medical care for patients in the anterior-MCA-MeVO group or patients in the posterior-MCA-MeVO group ( Figure 2 ), and no evidence of EVT effect modification by MCA occlusion location on 90-day mRS or any other outcome was seen. Conclusion: There was no significant association of MCA-MeVO occlusion location (anterior versus posterior) and post-thrombectomy outcomes and no EVT effect modification by occlusion location was seen in the ESCAPE-MeVO trial.

Abstract Background and aims Stroke patients with tandem carotid lesions constitute about 15-20% of patients undergoing endovascular thrombectomy (EVT). However, the optimal treatment of acute stroke in these patients remains uncertain with regards to addressing the ICA lesion during EVT or not. Methods To determine if acute cervical ICA stenting in addition to intracranial thrombectomy is superior to intracranial thrombectomy alone without acute cervical ICA stenting with regards to functional outcome at 90 days. Results EASI-TOC is an ongoing Canadian, pragmatic Phase III, multi-centre, prospective, randomized, open-label, blinded endpoint (PROBE) controlled trial. It will enroll 458 adult tandem patients undergoing EVT and randomize them (1:1) to either undergo acute ICA stenting during EVT (either before or after intracranial thrombectomy, as per clinician judgement) or undergo intracranial thrombectomy alone without ICA stenting. Conclusions The primary outcome is the proportion of patients achieving a favorable modified Rankin scale score (mRS 0-2) at 90 days and primary analysis will be by intention-to-treat. Our primary hypothesis assumes a greater proportion of patients with 90-day mRS 0-2 in the stenting group versus the no stenting group (55% versus 40%). Safety outcomes will include symptomatic intracerebral hemorrhage, procedural complications and death. Conflict of interest

Facial arteriovenous malformations (AVMs) are rare congenital disorders of angiogenesis that are known to cause hemorrhage. We present a case of uncontrolled bleeding from a known facial AVM during tooth extraction. The patient was transferred to a tertiary hospital where the patient underwent emergency endovascular embolization of the AVM. While facial AVMs are rare, their presence should be carefully considered when planning any oral-maxillofacial procedure. Multidisciplinary care should be considered when treating patients with facial AVMs.

BACKGROUND:The endovascular clip system (eCLIPs), a unique extra-saccular device for treatment of wide necked bifurcation aneurysms (WNBAs), was evaluated in the French eCLIPs efficacy and safety study (EESIS-FR). This paper summarizes the patient demographics, procedural characteristics, and 30 day adverse event (AE) data. METHODS:The EESIS-FR trial was a prospective study from 18 centers, enrolling 123 adults with WNBAs at the carotid (CT) and basilar (BT) termini. The study protocol was approved by a central ethics committee, had independent adjudication of AEs by a Clinical Events Committee, and had independent core laboratory adjudication of effectiveness outcomes. RESULTS:Mean age was 55.0±1.2 years (19-78 years); 73% were women. 43% and 57% of the aneurysms were located at BT and CT, respectively. Mean neck length was 4.8 mm, neck depth 4.2 mm, dome height 5.4 mm, and dome width 6.3 mm. Successful implantation was achieved in 115 cases (93%). Implant time averaged 36 min. Three primary safety events (2.4%) occurred within the first 30 days, all at the index procedure: subarachnoid hemorrhage (SAH) due to a distal guidewire perforation, death from SAH due to rupture of the aneurysm, and spinal cord infarction caused by an occlusive access catheter. Five minor strokes (4.1%) and three transient ischemic attacks (2.4%) occurred, all of which were procedurals. None of these patients had a modified Rankin Scale score of >2 at 30 days. No patient had further ischemic or hemorrhagic events beyond the periprocedural period to 30 days. CONCLUSION:eCLIPs treated WNBAs at BT and CT, with procedural safety and technical success similar to those with intrasaccular devices.

BACKGROUND:Patients with stroke due to symptomatic intracranial occlusion and concurrent symptomatic high-grade cervical internal carotid artery (ICA) stenosis (≥70%) or occlusion constitute 15%-20% of patients undergoing EVT. The optimal management of the cervical ICA in these tandem lesions remains unknown. We hypothesise that acute carotid artery stenting in addition to EVT will improve functional outcomes when compared with EVT alone. STUDY DESIGN:Endovascular Acute Stroke Intervention-Tandem Occlusion (EASI-TOC) is a multicentre, prospective, randomised, open-label, blinded end-point (PROBE) controlled trial. Adult patients with a disabling acute anterior circulation stroke (intracranial carotid, M1 or M2 segment occlusion) and salvageable brain tissue who undergo EVT within 24 h of onset, are eligible for enrolment if they have an angiographically confirmed atherosclerotic carotid tandem lesion. Patients are randomised 1:1 to acute carotid stenting or no stenting during EVT. STUDY ENDPOINTS:The primary outcome is the proportion of patients achieving a favourable functional outcome (mRS 0-2) at 90 days. Secondary outcomes include 12-month mRS, recanalisation, the 90-day rate of recurrent ipsilateral stroke or retinal ischaemia, the proportion of patients with ICA thrombosis, 90-day Montreal Cognitive Assessment score and quality of life. Safety outcomes include any ICH, sICH, all-cause mortality and procedural complications. SUMMARY:Endovascular Acute Stroke Intervention-Tandem Occlusion is a pragmatic trial addressing a critical gap in the acute management of patients with tandem carotid lesions by evaluating whether acute carotid stenting provides a functional benefit over no stenting in patients undergoing EVT. TRIAL REGISTRATION:ClinicalTrials.gov NCT04261478.

Introduction: Despite the success of endovascular thrombectomy (EVT) for ischemic stroke, complications such as intracerebral hemorrhage (ICH) occur. In individual studies, the Alberta Stroke Program Early CT Score (ASPECTS) predicts ICH risk, but comprehensive data are lacking. We conducted a systematic review and pooled patient meta-analysis to evaluate the association between ASPECTS and ICH after EVT. Methods: We searched MEDLINE, EMBASE, CINAHL, PsycINFO, Web of Science, and Cochrane from January 1, 2012, to July 1, 2024. We included randomized controlled trials and prospective observational studies of patients ≥18 years old with anterior circulation ischemic stroke on CT, CTP, or DWI-MRI who underwent EVT within 24h of symptoms onset. The primary outcome was the association between ASPECTS and symptomatic ICH; the secondary outcome was ASPECTS and any ICH. For the meta-analysis, we conducted an exploratory analysis to identify covariates for the multivariable model. Odds ratios (OR) with 95% CI were calculated, adjusting for hypertension, diabetes, National Institutes of Health Stroke Scale (NIHSS) score, time from symptoms onset to randomization, and modified Thrombolysis in Cerebral Infarction (mTICI) score. Results: A total of 3,290 studies were screened, with 31 selected for full-text review. Thirteen met inclusion criteria: 11 randomized controlled trials and 2 prospective observational studies. Symptomatic ICH rates ranged from 0–11.7%, and any ICH from 2.8–91.5%. Data from DEFUSE3, ESCAPE, ESCAPE-NA1, and IMS3 were included in the patient-level meta-analysis, comprising a total of 1,182 patients. A 1-point lower ASPECT score was not associated with higher odds of symptomatic ICH (OR 1.01; 95% CI 0.90, 1.14; p=0.84) but was associated with higher odds of any ICH (OR 1.19; 95% CI 1.12, 1.27; p<0.0001). Compared with ASPECT score 9–10, categories 6–8, 3–5, and 0–2 were all associated with increased odds of any ICH (Table 1). Conclusion: In this patient-level meta-analysis, a lower ASPECT score was significantly associated with higher odds of any ICH, but not symptomatic ICH. These findings provide important information on complications in patients with larger stroke burden treated with EVT.

BACKGROUND:The Alberta Stroke Program Early CT Score (ASPECTS) and CT angiography (CTA) Collateral Score (CS) are routinely used to estimate ischemic core burden and collateral status in acute ischemic stroke due to large vessel occlusion, but suffer from limited reliability. Whether automated CT perfusion (CTP) maps improve scoring consistency remains unclear. OBJECTIVES:To assess the reliability of these scores on non-contrast computed tomography (NCCT) and CTA among numerous raters, with and without access to automated perfusion maps, and their correlations with endovascular thrombectomy (EVT) decisions. METHODS:Twenty-nine clinicians independently rated 60 imaging cases from 30 late-window stroke patients with large vessel occlusion, each presented twice: once using NCCT and CTA alone ('non-CTP cases'), and once with the addition of perfusion maps ('CTP cases'). Twenty-eight raters (97%) completed the survey twice. Inter- and intra-reliability was assessed using Gwet's AC1/2 coefficients (κG). Correlations with EVT decisions were evaluated using Cramer V. RESULTS:Inter-rater reliability for ASPECTS was substantial and similar between non-CTP (κG = 0.65, 95% CI: 0.53 to 0.78) and CTP cases (κG = 0.64, 95% CI: 0.51 to 0.77). CS showed an almost perfect reliability in both scenarios (κG= 0.82 and 0.83). Intra-rater agreement was at least substantial. Dichotomizing ASPECTS as 0-2/3-10 improved reliability to almost perfect. ASPECTS strongly correlated with EVT decisions (V=0.80), whereas CS showed moderate correlation (V=0.56), both remaining similar with the addition of CTP (V=0.75 and 0.54, respectively). CONCLUSION:Automated perfusion imaging did not improve the reliability of ASPECTS or CS. Strong reliability was achieved with NCCT and CTA alone.

BACKGROUND:Cerebral angiography cannot directly assess the intimal surface of a vessel. The MicroAngioscope is a small and flexible catheter that allows visualization of the inside of the cerebral vasculature. Our objective is to report our first-in-human experience with the live visualization of intracranial vasculature using the MicroAngioscope. METHODS:This was a prospective, single-arm, national multi-center observational study of consecutive intracranial endovascular cases treated using the MicroAngioscope as an adjunct. This first-in-human study aimed at assessing the safety of the technology by prospectively collecting any procedural complications. A secondary end point was the successful visualization of the vasculature and the implants. RESULTS:The MicroAngioscope, used in 31 cases, was successfully delivered to the location of interest and allowed for a direct live visualization of the condition and the implant that had been deployed. There was no vessel injury based on cerebral angiography. The cases included 9 cases of carotid stent, 6 cases of flow diversion, 11 cases of transverse sinus stenting, 2 cases of aneurysm intrasaccular flow-disruption, 1 case of aneurysm treatment with stent-assisted coiling, and 2 cases of mechanical thrombectomy. All cases were successfully completed without complications. All patients were neurologically unchanged following their respective procedures. Angioscopy was helpful in making the diagnosis in the case of the carotid web, assessing vessel wall apposition immediately after flow diverter and venous stent deployment, and assessing the degree of strut coverage in both arterial and venous stents in follow-up. CONCLUSIONS:This First-in-Human study demonstrated the early feasibility and safety of the MicroAngioscope in neurointerventional procedures. Further studies are needed to determine its relevance in daily practice.

BACKGROUND:Randomized trials showed that endovascular thrombectomy (EVT) did not improve outcomes in medium vessel occlusion (MeVO) stroke compared with usual care. We investigated whether patients randomized to EVT who achieved near-complete/complete reperfusion had improved clinical outcomes compared with patients randomized to usual care. METHODS:Post-hoc analysis of ESCAPE-MeVO, which randomized patients with MeVO stroke to undergo EVT in addition to usual care or usual care only. Reperfusion grade in EVT patients was assessed with the MeVO expanded Thrombolysis in Cerebral Infarction (meTICI) score. Regression analyses were used to compare clinical outcomes between EVT patients with near-complete/complete (meTICI 2c-3) reperfusion and usual care patients, and the association between reperfusion grade and clinical outcomes in EVT patients. RESULTS:Overall, 253 of 255 (99.2%) patients randomized to EVT had final meTICI scores, of whom 133 (52.2%) achieved meTICI 2c-3 reperfusion. Infarct volumes were lower in EVT meTICI 2c-3 patients than in usual care patients, but there were no significant differences between EVT meTICI 2c-3 and usual care patients for 90-day modified Rankin Scale (mRS) score (adjusted common OR 1.17, 95% CI 0.79 to 1.75). Higher final meTICI scores were associated with improved 90-day mRS and lower infarct volumes in EVT patients. CONCLUSION:Although higher reperfusion grade was associated with smaller infarct volumes, there was no statistically significant difference in 90-day mRS between patients achieving meTICI 2c-3 and those receiving usual care.

Background: Endovascular thrombectomy (EVT) is standard care for patients with acute ischemic stroke secondary to large-vessel occlusion (LVO), but recently, three randomized controlled trials found no overall benefit in EVT treatment for medium-vessel occlusion (MeVO) compared to medical therapy alone. Given clinical and anatomical differences in anterior and posterior circulation MeVOs, we hypothesized that response to EVT treatment for MeVOs may differ according to location. Methods: We analyzed data from the ESCAPE-MeVO trial. Interaction between EVT and vessel occlusion location was assessed with the Mantel-Haenszel test of homogeneity reported as a crude combined risk ratio (RR). We further performed stratified analyses examining for a difference in treatment effect by anterior (A2, A3, M2, M3) and posterior (P2, P3) circulation occlusion. The anatomical definitions and frequencies of the different occlusion sites are shown in Figure 1. We used logistic regression to compare the odds of 90-day excellent outcomes (modified Rankin Scale [mRS] 0–1) within stratums. Secondary outcomes included 90-day mortality, MeVO-extended thrombolysis in cerebral infarction (meTICI) score, infarct volume, and symptomatic intracranial hemorrhages (sICH). Results are reported as adjusted odds ratios (aOR), adjusted for age, sex, baseline National Institute of Health Stroke Scale (NIHSS), intravenous thrombolysis (IVT) use, and time from symptom onset to randomization. Results: Of the 529 patients in ESCAPE-MeVO, 473 had anterior MeVOs while 56 had posterior MeVOs (Figure 1). There was no evidence of effect modification of treatment by occlusion location (test of homogeneity, p=0.45; the crude unadjusted RR [JO3] was 0.97 (95%CI 0.79 – 1.18). Stratified, adjusted analyses (Figure 2) showed no benefit of EVT over medical therapy for the anterior circulation group (aOR 0.87 [95% CI 0.59-1.30]) and for the posterior circulation group (aOR 1.86 [95% CI 0.46-7.71]). Finally, there were no significant differences between EVT and medical therapy in the odds of 90-day mortality or sICH based on location. Conclusion: Anterior and posterior MeVO patients had similar responses to EVT, with neither of the two groups benefitting from it. Interpretation of our results is limited by the small sample size of patients in the posterior circulation MeVO group.

Importance Chronic subdural hematomas commonly recur after surgical drainage. The effect of adjunctive embolization of the middle meningeal artery (EMMA) on recurrence risk remains unclear. Objective To evaluate whether EMMA as an adjunct to surgical drainage reduces chronic subdural hematoma recurrence compared with surgery alone. Design, Setting, and Participants This trial was a randomized, open-label, blinded–end point trial involving adults with unilateral, symptomatic chronic subdural hematoma (≥10 mm) undergoing surgical drainage across 9 tertiary care centers in Canada between August 2021 and April 2025. Intervention EMMA using a liquid embolic agent (Onyx-18) within 72 hours after surgical drainage vs a control group that did not receive EMMA after surgical drainage. Main Outcomes and Measures Primary outcome was symptomatic recurrence of chronic subdural hematoma detected on computed tomographic (CT) scan at 90 days (range, 60 to 120 days). Secondary outcomes included radiographic recurrence of chronic subdural hematoma, 90-day mortality, and serious adverse events. The last date of follow-up was July 27, 2025. Results Of 192 randomized participants, 186 (mean age, 71.8 years; 136 male [73%]) completed the trial (93 per group). The primary outcome of symptomatic recurrence of chronic subdural hematoma detected on CT scan occurred in 4 participants (4.3%) in the EMMA group vs 26 patients (28%) in the control group (risk difference, −23.7; 95% CI, −34.1 to −13.9; P < .001). Radiographic recurrence occurred in 13 participants (14%) in the EMMA group vs 46 patients (49.5%) in the control group. Mortality was 4.3% vs 1.1%; serious adverse events occurred in 8.6% vs 5.4%, respectively. Conclusions and Relevance Adjunctive EMMA after surgical drainage significantly reduced symptomatic recurrence on CT scan of unilateral chronic subdural hematoma at 90 days compared with surgery alone. Trial Registration ClinicalTrials.gov Identifier: NCT04750200

OBJECTIVE Many patients recruited in the Treatment of Brain Arteriovenous Malformations Study (TOBAS) are managed conservatively. The aim of this study was to monitor what happened to those patients. METHODS TOBAS comprises two randomized controlled trials and multiple prospective registries. All patients with brain arteriovenous malformations (AVMs) can participate. This report concerns patients selected for conservative management. The primary trial outcome measure is related death or dependency (modified Rankin Scale [mRS] score > 2) at 10 years. Secondary outcomes include intracranial hemorrhages, nonhemorrhagic neurological events, and serious adverse events (SAEs). For this report, outcome results are presented using patient-years, Kaplan-Meier survival curves, and Cox log-rank tests. There was no blinding. RESULTS From June 2014 to May 2021, 1010 patients were recruited, of whom 498 (49%) were proposed the prospective observation registry. After exclusions, 434 (87%) patients remained for analysis. The majority of patients had unruptured AVMs (378/434 [87%]), of which 195 (52%) were low grade (Spetzler-Martin grade I or II). During a mean follow-up period of 3.2 years (total 1368 patient-years), the primary outcome occurred in 23 of 434 (5%) patients, corresponding to an incidence of 1.7 (95% CI 1.1-2.5) per 100 patient-years. For unruptured AVMs the incidence was 1.1 (95% CI 0.7-1.9) per 100 patient-years, and for low-grade unruptured AVMs it was 0.6 (95% CI 0.2-1.7) per 100 patient-years. Poor outcomes were more frequent in patients with a history of rupture (HR 5.6 [95% CI 2.4-13.0], p < 0.001), infratentorial AVMs (HR 2.9 [95% CI 1.1-7.3], p = 0.027), and age >= 55 years (HR 3.2 [95% CI 1.4-7.6], p = 0.007). Major intracranial hemorrhage occurred in 35 of 434 (8%) patients (incidence of 2.6 [95% CI 1.9-3.6] per 100 patient-years; 2.0 [95% CI 1.3-2.9] per 100 patient-years for unruptured AVMs and 1.3 [95% CI 0.6-2.6] per 100 patient-years for low-grade unruptured AVMs). Major AVM hemorrhages were more frequent in ruptured (HR 4.4 [95% CI 2.1-8.9], p < 0.001), large (HR 2.6 [95% CI 1.1-6.6], p = 0.039), and high-grade (HR 2.5 [95% CI 1.2-5.3], p = 0.013) AVMs and those with deep venous drainage (HR 2.1 [95% CI 1.1-4.2], p = 0.032). SAEs occurred in 48 of 434 (11%) patients (incidence of 3.6 [95% CI 2.7-4.8] per 100 patient-years). For unruptured AVMs the incidence was 2.8 (95% CI 2.0-4.0) per 100 patient-years, and for low-grade unruptured AVMs it was 1.8 (95% CI 1.0-3.2) per 100 patient-years. CONCLUSIONS Nearly half of TOBAS participants were observed. Rates of untoward neurological events were within expected boundaries.

Magnetic resonance angiography (MRA) is a commonly used non-invasive imaging modality for the follow-up of treated intracranial aneurysms. The 3-category Montreal classification system is widely used to evaluate treatment outcomes, including aneurysms treated with Woven EndoBridge (WEB) devices or coils. This study aimed to assess the reliability and clinical implications of the Montreal scale for aneurysms imaged with MRA. An electronic portfolio of 60 aneurysms (30 treated with WEB devices and 30 with coils) was evaluated by 30 raters from diverse clinical backgrounds. Raters graded aneurysm occlusion using the Montreal classification system and provided management recommendations (delayed follow-up, close follow-up, or re-treatment). Twenty-three raters completed a second evaluation of permuted cases after one month. Reliability was assessed using Gwet’s AC2 (κG) coefficients, and the correlation between occlusion grade and management recommendation was analyzed with Cramer’s V. Inter-rater agreement for occlusion grades was substantial (κG = 0.70; 95

The assessment of collateral circulation is an important prognostic factor in patients with stroke due to large vessel occlusion. The results of a recent trial suggested that collateral status could even be used for thrombectomy decision making in patients with late window acute ischemic stroke. However, the reliability of collateral assessment is uncertain. We sought to assess the interrater and intrarater agreement of collateral assessment using multiphase CT angiography. Two junior and two senior raters in stroke neurology, diagnostic neuroradiology, and interventional neuroradiology evaluated 60 multiphase CT scans of acute ischemic stroke and scored the presence of collaterals as follows: poor (< 50

ObjectiveMechanical thrombectomy (MT) is well-established for the treatment of acute ischemic stroke (AIS) from large vessel occlusion (LVO), with growing data supporting the expansion to distal and medium vessel occlusions (DMVO). Despite successful recanalization in DMVO, certain patients still experience poor long-term clinical outcomes, prompting our study to comprehensively explore pre-MT factors influencing outcome despite excellent recanalization (final modified Thrombolysis in Cerebral Infarction [mTICI] score ≥2c).MethodsWe retrospectively examined data from patients who consecutively underwent MT for a primary middle cerebral artery (MCA) DMVO across 37 centers in North America, Asia, and Europe. We identified baseline clinical and imaging factors associated with poor clinical outcome (defined as a modified Rankin Scale [mRS] score of 3-6) at 3 months, despite excellent recanalization using a multivariable model.ResultsBetween September 2017 and July 2021, 623 patients achieved mTICI > 2b and they were included in our study. Among them, 198 (32%) experienced a poor clinical outcome (mRS 3-6). Predictors of poor clinical outcome included higher age (OR 1.05 [1.03-1.07], p < 0.001), higher NIHSS at admission (OR 1.12 [1.08-1.15], p < 0.001), higher baseline mRS (OR 1.77 [0.96-3.26], p = 0.067), and diabetes (OR 1.59 [1.01-2.48], p = 0.044). Higher ASPECTS was associated with a decreased risk of poor clinical outcome (OR 0.82 [0.71-0.94], p = 0.006).ConclusionOlder age, diabetes, higher baseline mRS, and NIHSS were associated with poor clinical outcome in MCA DMVO despite excellent recanalization. Conversely, a higher ASPECTS decreased the probability of such an outcome.

BACKGROUND AND OBJECTIVES:Although carotid endarterectomy (CEA) or carotid artery stenting (CAS) is recommended for symptomatic extracranial carotid stenosis of 50-99%, the COVID-19 pandemic significantly impacted resources. CAS therefore offered potential advantages as access to the angiosuite was seemingly easier than access to operating rooms. The primary objective was to determine the frequency of serious and non-serious complications following CAS before and during the COVID-19 pandemic. METHODS:We performed a retrospective cohort study of consecutive patients who received CAS at the Ottawa Hospital, Canada, from June 2019 to May 2021. We reviewed baseline demographics, imaging, as well as intraprocedural and postprocedural complications based on chart review. We performed multivariable logistic regression to determine associations between clinical and safety outcomes. RESULTS:We included 47 patients in the pre-pandemic period and 93 patients in the pandemic period (mean age = 70.4 years; 54% female; P = 0.287 for age and P = 0.962 for sex, respectively). The combined rate of intraprocedural and postprocedural serious complications (ischemic stroke, intracerebral hemorrhage, myocardial infarction or death) was 7.1%. Eight strokes occurred, and one patient with a postprocedural ischemic stroke died 11 days after stenting. Complication rates were similar before and during the pandemic (aOR 1.040, 95% CI 0.466-2.321). The number of referrals for CEA during the pandemic period decreased by 50%. CONCLUSION:In this cohort of consecutive patients undergoing CAS at a Canadian comprehensive stroke center before and during the COVID-19 pandemic, the rates of stroke and death were similar to pre-pandemic conditions and were generally consistent with the published literature.

Objective The novel coronavirus disease 2019 (COVID-19) pandemic led to the implementation of wide-ranging institutional infection control protocols. The purpose of this study is to determine the effect of the pandemic on outcomes of large vessel occlusion (LVO) acute ischemic stroke (AIS) patients treated with endovascular therapy (EVT). Materials and methods Data were obtained from prospectively collected quality improvement stroke databases at six Canadian comprehensive stroke centres from March 11, 2020 to March 11, 2021. This patient cohort was compared to pre-pandemic patients consecutively treated with EVT from March 11, 2019 to March 10, 2020. The primary outcome is a 90-day modified Rankin Score (mRS). The secondary outcomes are angiographic time metrics. Results A total of 1329 EVT patients (pre-pandemic n = 666) were included. The initial NIHSS was statistically significantly lower in the pandemic cohort. Other baseline patient characteristics were comparable between the two periods. Median (interquartile range, IQR) time from last seen normal (LSN) to emergency department (ED) (172 (68-316) vs 210 (97-382) min; p = 0.0001), LSN to puncture (235 (160-378) vs 280 (184-475); p < 0.0001), computed tomography (CT) to angiographic table (68 (44-108) vs 84 (57-125) min; p = 0.002), ED to angiographic table (65 (37-96) vs 80 (50-112) min; p = 0.001), CT to recanalization (117 (84-156) vs 130 (89-173) min; p = 0.038) and LSN to recanalization (279 (198-453) vs 327 (219-561) min; p = 0.002) were longer in the pandemic period as compared to the pre-pandemic. There were no significant differences in median time from angiographic table to arterial puncture (13 (8-19) vs 12 (9-16) min; p = 0.70) or arterial puncture to first pass (21 (14-31) vs 20 (14-30) min; p = 0.50). Patients were more likely to have favourable outcomes (mRS at 90 days score of <= 2) post-EVT pre-pandemic than pandemic (53% vs 44%; p = 0.02). Furthermore, analysis of the time interval from "LSN to arterial puncture" in relation to functional outcomes showed that the percentage of unfavorable outcomes increased among patients who underwent EVT within 240 minutes. Specifically, the rate of unfavorable outcomes rose from 32.9% to 42.9% (p = 0.37 for intervals under 150 minutes) and from 41.6% to 52.3% (p = 0.15 for intervals between 151 and 240 minutes) when comparing pre-pandemic to pandemic periods. However, the detrimental effect associated with the pandemic was diminished in patients who received EVT beyond 240 mins (p = 1.0). Conclusion In this multicenter study involving six Canadian stroke centers, patients exhibited a higher probability of unfavorable long-term functional outcomes following EVT during the pandemic period compared to those in the pre-pandemic cohort, particularly during the first year of the pandemic.

BACKGROUND AND AIMS:Achieving a first pass recanalization (FPR) improves clinical outcomes in patients with basilar artery strokes, but its association with initial infarct burden is unknown. We aimed to study the benefits of FPR for basilar artery strokes by initial infarct burden using the Posterior Circulation Alberta Stroke Program Early CT score (pc-ASPECTS). METHODS:We retrospectively analyzed the prospective multicentric Endovascular Treatment of Ischemic Stroke registry and included 194 patients diagnosed with an acute basilar artery occlusion who were treated with thrombectomy. Our primary outcome was a modified Rankin Scale (mRS) of 0-3 at 90 days, and our secondary outcomes were an mRS of 4-6 and mortality. We compared the 90-day clinical outcomes of achieving an FPR versus multiple thrombectomy passes based on patients' initial infarct size on pretreatment MRI: small (pc-ASPECTS = 9-10), medium (pc-ASPECTS = 6-8) and large (pc-ASPECTS <6). RESULTS:Patients with a medium or large infarct size had significantly better outcomes (mRS 0-3 at 3 months) if FPR was achieved than if multiple passes were required (RR = 1.61, 95% CI: 1.16, 2.24; p-value = 0.005; and RR = 3.41, 95% CI: 1.54-7.57; p-value = 0.003, respectively). No similar difference was seen among patients with small infarcts. Achieving an FPR was also associated with a significantly lower mortality risk among patients with a moderate infarct size (RR = 0.36, 95% CI: 0.17-0.79; p-value = 0.010) but not with those with small or large infarcts. CONCLUSIONS:Achieving an FPR significantly improves clinical outcomes in acute stroke patients with basilar artery occlusions undergoing thrombectomy when their infarcts are medium or large. Ongoing research to develop surgical techniques to achieve FPR is crucial to improving patients' prognoses.

The vast majority of patients with minor stroke achieve what are considered good or excellent outcomes on the modified Rankin Scale (0-1/0-2), yet many are dissatisfied with their outcomes. There is a need for a functional outcome measure tailored for minor stroke that better reflects the spectrum of clinical outcomes within this population. We developed the Canadian Outcome Scale for Minor Stroke (COSMOS) and performed an interrater and intrarater reliability study. COSMOS is a 7-point scale ranging from 0 (no symptoms) to 6 (loss of independence for an instrumental or basic activity of daily living or worse), which accounts for performance limitations and losses of a person's hobbies or passions and of their employment, educational, service, or caregiving pursuits, besides just activities of daily living. One hundred test case vignettes were developed. Stroke physicians, fellows, and research nurses/staff were invited to review training materials and provide the COSMOS grade for 20 cases representing all COSMOS grades (0-6). After a minimum 2 weeks' wash-out period, participants were asked to grade the same 20 cases again. Interrater and intrarater agreement were assessed using Cohen κ, weighted κ, percentage agreement, and intraclass correlation coefficient. Among 33 participants (18 attending physicians, 9 stroke fellows, and 6 research staff/nurses; median 12.5 years of experience), COSMOS had substantial interrater reliability (80.5% agreement [95% CI, 75.7%-85.3%]; Cohen κ, 0.77 [95% CI, 0.72-0.84]) and almost-perfect intrarater reliability overall (87.1% agreement [95% CI, 84.4%-89.7%]; Cohen κ, 0.85 [95% CI, 0.82-0.88]); weighted κ showed almost perfect agreement for both interrater (0.88 [95% CI, 0.85-0.92]) and intrarater reliability (0.92 [95% CI, 0.90-0.94]). The overall chance-adjusted simultaneous intrarater/interrater agreement using intraclass correlation coefficient was 0.95 (95% CI, 0.94-0.97). Results were similar with substantial to almost-perfect agreement when considering key subgroups based on position (attendings, fellows, research nurses/staff) and years of experience. In conclusion, the newly proposed COSMOS scale demonstrated substantial interrater and intrarater reliability. The scale merits further study in cohort studies and clinical trials of minor stroke.